package com.ali.springcloud.lb;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author ：ALi
 * @date ：Created in 2022/7/3 10:45
 * @description：LoadBalabcer的实现类
 * @modified By：
 * @version: $
 */
//自定义轮询实现类
@Component
@Slf4j
public class LoadBalancerImp implements LoadBalancer {

    private AtomicInteger atomicInteger = new AtomicInteger(0);

    //得到下一个服务地址的下标
    public final int getAndIncrement(){
        int current;
        int next;
        do{
            current = this.atomicInteger.get();
            next = current >= 2147483647 ? 0:current+1;
        }while(!this.atomicInteger.compareAndSet(current,next));
        log.info("next:"+next);
        return next;
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement() % serviceInstances.size();

        return serviceInstances.get(index);
    }
}